Internet protocol (IP) telephones, also referred to as voice-over-Internet protocol (VOIP) telephones provide an alternative to subscriber-line services and equipment and to other offerings such as cable telephone and in business and hotel environments, to traditional multi-line key or PBX systems. IP telephones are increasing in popularity, due to the portability of the telephone connection and relatively low cost compared to other fixed-location services.
For office locations, an IP telephone set resembling a traditional key/PBX exchange telephone set is frequently employed as the telephone device, or in hotels, IP phones having fully-featured hotel services button sets are deployed. IP desktop telephones typically include a direct connection such as an Ethernet port, eliminating the need for another device, such as a personal computer, to interface the IP telephone to the Internet for a single connection. Relatively low-cost controllers capable of routing to multiple IP telephones further increase the flexibility and cost-savings available by using IP telephones in the office and hotel environments. As the popularity of IP telephones increases, IP desktop telephones can also expect to proliferate in the home environment, as well.
In office and hotel environments in particular, where large numbers of devices are typically left unused on weekends and more than ten hours per day on weekdays, the power consumption of personal computers and monitors is reduced by having the devices automatically enter a low power consumption state. However, typical IP telephones typically do not implement such a low-power state, as the display on the telephone generally needs to remain visible and the network connection must be maintained in order to receive an event that indicates a call has been received. The power consumed by a network interface is substantial, and the use of LAN interfaces for the IP telephone interfaces in the latest commercially-available models, further increases power consumption.
Subscriber-line telephones traditionally needed no low-power mode, as when on-hook, all of the telephone electronics is disconnected, with the exception of the ringer. While some telephones having backlit liquid-crystal (LCD) displays employ backlight dimming after some period of inactivity, telephone devices do not typically operate in a manner similar to personal computers and computer monitors.
Therefore, it would be desirable to provide an IP telephone and method for power management that conserves energy by placing the IP telephone in a low-power operating mode when full power consumption is not necessary.